1. Field of the Invention
This invention relates to a hybrid circuit device wherein a delay line is externally connected to an integrated circuit.
2. Description of the Prior Art
It is the recent trend that most electronic circuits are provided in the form of an integrated circuit. However, difficulties have been experienced in fabricating, in the form of an integrated circuit, an inductance containing circuit such as a delay line circuit which consists of a combination of coils and capacitors, for example. Thus, in the case of a circuit device including an integrated circuit and an element or elements which are difficult to provide in the form of an integrated circuit, it is required that such elements be externally connected to the integrated circuit. Such requirement also arises when a delay line is to be connected to a saturation type logical circuit such as TTL or the like.
Referring to FIG. 1 of the accompanying drawings, there is shown, in a perspective view, a conventional hybrid circuit wherein a coil 12 and capacitors 13, which together constitute a delay line, are fixedly mounted on a dual in-line package (referred to as DIP hereinafter) 11 of saturation type logical circuit formed by using a transfer molding technique; and the delay line is connected to a saturation type logical circuit which is formed by an integrated circuit, by winding and soldering the lead wires of the delay line onto upwardly bent terminals 15 and downwardly bent terminals 16 of the DIP 11.
As shown by the dotted line in FIG. 1, the foregoing hybrid circuit device is hermetically packaged, as a whole, with a plastic material, with only lower portions of the downwardly bent terminals 16 being exposed below the DIP 11, by using an injection molding technique.
However, the aforementioned conventional arrangement is disadvantageous in that the terminals, which are upwardly bent 180.degree., of the once completed DIP 11 are weakened and thus liable to be broken. Moreover, tediousness is experienced in carrying out the procedures of winding and soldering the lead wires 14 onto the terminals 15 and 16. More seriously, the solder tends to flow along the terminals, thus making the soldering incomplete. Another disadvantage is that the resulting hybrid circuit device becomes bulkier due to the fact that the DIP, which is bulky in itself, and delay line are plastic-molded together. The size of the thus obtained hybrid circuit device is greater than the standardized size for a DIP provided by means of transfer molding technique; hence, it is not possible to employ a DIP fabricated by using the transfer molding technique. This means that the aforementioned conventional arrangement turns out to be inferior in terms of appearance and commercial value as well as reliability of the plastic-packaging thereof.